add 8 reserved bytes to -z protocol

navrecv.cc

@@ -14,6 +14,7 @@
 #include "zstdwrap.hh"
 #include "CLI/CLI.hpp"
 #include "version.hh"
+#include <netinet/tcp.h>
 
 static char program[]="navrecv";
 
@@ -141,6 +142,7 @@ void writeToDisk(time_t s, uint64_t sourceid, std::string_view message)
 // note that this moves the socket
 void recvSession2(Socket&& uns, ComboAddress client)
 {
+  string secret = SRead(uns, 8); // ignored for now
   cerr << "Entering compressed session for "<<client.toStringWithPort()<<endl;
   ZStdReader zsr(uns);
   int s = zsr.getFD();
@@ -174,6 +176,9 @@ void recvSession2(Socket&& uns, ComboAddress client)
     denum = htonl(denum);
     //    cerr<<"Received message "<<denum<< " "<<nmm.localutcseconds()<<" " << nmm.localutcnanoseconds()/1000000000.0<<endl;
     writeToDisk(nmm.localutcseconds(), nmm.sourceid(), out);
+    
+    SSetsockopt(uns, IPPROTO_TCP, TCP_CORK, 1 );            
+
     SWrite(uns, num);
   }
 }

nmmsender.cc

@@ -6,7 +6,7 @@
 #include "navmon.hh"
 #include <algorithm>
 #include "zstdwrap.hh"
-
+#include <netinet/tcp.h>
 using namespace std;
 
 void NMMSender::sendTCPThread(Destination* d)
@@ -45,7 +45,8 @@ void NMMSender::sendTCPThread(Destination* d)
         };
         std::unique_ptr<ZStdCompressor> zsc;
         if(d_compress) {
-          sc.writen("RNIE"); // the other magic value is "bert". hence. 
+          sc.writen("RNIE00000000"); // the other magic value is "bert". hence.
+          // the 00000000 is a placeholder for a "secret" we might implement later
           zsc = std::make_unique<ZStdCompressor>(emit, 20);
         }
         bool hadMessage=false;
@@ -111,6 +112,9 @@ void NMMSender::sendTCPThread(Destination* d)
             }
             hadMessage = false;
             usleep(100000);
+#ifdef __linux__
+            SSetsockopt(s, IPPROTO_TCP, TCP_CORK, 1 );
+#endif
 
           }
         }

ubxtool.cc

@@ -566,7 +566,7 @@ int main(int argc, char** argv)
       }
       if (doDEBUG && m8t) { cerr<<humanTimeNow()<<" Detected timing module"<<endl; }
       if (doDEBUG) { cerr<<humanTimeNow()<<" Sending serial number query"<<endl; }
-      msg = buildUbxMessage(0x27, 0x03, {});
+      msg = buildUbxMessage(0x27, 0x03, {}); // UBX-SEC-UNIQID
       um1=sendAndWaitForUBX(fd, 1, msg, 0x27, 0x03); // ask for serial
       serialno = fmt::sprintf("%02x%02x%02x%02x%02x",
                               um1.getPayload()[4],